Beam compass



Oct. 3, 1961 A. D. BENNETT, JR

BEAM COMPASS 2 Sheets-Sheet 1 Filed Feb. 14, 1958 in .i NW N wm M 0m P QWm m T we ::::c m 00. 2 OVI' Wm mm LY @N W AB @V Nw O h m NN vm W0 G WmOct. 3, 1961 A. D. BENNETT, JR

BEAM COMPASS Filed Feb. 14, 1958 2 Sheets-Sheet 2 nTfllllmn INVENTOR.ALBE m D Senna-133v. BY

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ATTOEMEYS 3,002,280 BEAM (IGMPASS Albert D. Bennett, in, 3109 CornwallRoad, Columbia, SC. Filed Feb. 14, 1958, Ser. No. 715,240 3 Claims. (Cl.33--27) This invention relates to inscribing devices and, morespecifically, the present invention pertains to a drafting instrument.

One of the primary objects of this invention is to provide a beamcompass which may be quickly set roughly to a desired radius togetherwith fine adjusting means for obtaining the exact radius.

Another object of this invention is to provide in a beam compass aradial beam which comprises a length of wire or a length of a solid bar.

A further object of this invention is to provide in a beam compass a penholding base in which is incorporated means for finally adjusting theradial beam thereof, together with means for releasably locking theradial beam in its adjusted position.

A still further object of this invention is to provide a stabilized penholding base for a beam compass of the type generally referred to suprawhereby the base, upon release thereof by the draftsman, mechanic, oroperator will remain substantially upright.

It is still another object of this invention to provide in a beamcompass an inscn'ber housing with means for detachably connecting thesame to one end of the radial beam, the housing also being provided withmeans for its stabilization whereby upon release thereof by the operatorthe housing will remain substantially upright.

This invention contemplates, as a still further object thereof, theprovision of a beam type compass of the type generally referred toabove, the compass being non-complex in construction and assembly,inexpensive to manufacture, and durable in use.

Other and further objects and advantages of the present invention willbecome more evident from a consideration of the following specificationwhen read in conjunction with the annexed drawings, in which:

FIGURE 1 is a top plan view of a beam type compass constructed inaccordance with the teachings of this invention;

FIGURE 2 is a longitudinal cross-sectional view taken substantially onthe horizontal plane of line 2-2 of FIGURE 1, looking in the directionof the arrows;

FIGURE 3 is a vertical cross-sectional view, partly in elevation, thisview being taken on the line 3--3- of FIGURE 2, looking in the directionof the arrows;

FIGURE 4 is a transverse detail cross-sectional view taken substantiallyon the horizontal plane of line 4-4 of FIGURE 2, looking in thedirection of the arrows;

and

FIGURE 5 is a bottom plan view of the beam type compass illustrated inFIGURE 1.

Referring now more specifically to the drawings, reference numeraldesignates, in general, a beam type compass constructed inaccordancewith this invention. The compass 10 is seen to comprise anelongated cylindrical normally upright main body portion 12 having anenlarged cylindrical flange 14 at the lower end thereof. A bore 16extends inwardly from the lower end of the flange 14 in co-axialalignment with the main body portion 12, and the inner end of the bore16 is in open communication with an undercut circumferential recess orgroove 18 which rotatably receives a cylindrical flange 20integrallyconnected with the upper end of a depending substantially square rod 21to the sides of which are secured a plurality of radially spaceddownwardly extending and outwardly diverging stabilizing standards 22.As is seen Patented Get. 3, 1961 in the drawings, the upper ends of thestandards 22 project through the bore 16. The standards 22 serve tosupport the main body portion 12 in a normally upright position on asupport surface 24.

The main body portion 12 has a cylindrical bore 26 which extendsdiametrically therethrough adjacent the flange 14. The bore 26,intermediate its ends and at the upper side thereof communicates with arecess 28. The bore 26 receives for reciprocation therethrough anelongated cylindrical rack gear 30. From the upper side of said rackgear 30 projects a plurality of axially extending, uniformly spaced, andradially projecting gear teeth 32. I am teeth 34, 36 are provided ateach respective end of the rack gear 30. A worm gear 38 having a shaft40 meshes with the gear teeth 32 to effect reciprocation of the rackgear 30. The opposed ends of the shaft 40 are rotatably supported on themain body portion 12 and one end thereof extends exteriorly therebeyondand is enlarged and cut to form the gear 42. The gear 42. meshes with asecond gear 44 from one side of which extends a cylindrical integrallyformed centrally positioned shaft 46 suitably mounted for rotation inthe main body portion 12, the shaft 46 being vertically spaced from theshaft 40 and extending substantially parallel thereto. An enlargedmanually manipulative cylindrical knob 48 is integrally connected withthe gear 44 and projects laterally from the other side thereof.

Thus, as the knob 48 is rotated in a clockwise or in a counterclockwisedirection, the gear rack 30 reciprocates to the left or right (usingFIGURE 2 as a referral point).

The upper end of the main body portion 12 is provided with acircumferential groove 50 which rotatably receives an inturned radialflange 52 of a cap 54 which extends across the upper end of the mainbody portion 12.

As is seen in the drawings, the lower end of the rod 21 terminates abovethe lower ends of the standards 22 to provide a substantiallyrectangular passage 56 through which extends the pointed end 58 of anon-rotatable pivot pin 60, the other end of which is fixedly secured,by conventional means, to the lower end of the rod 21.

The rack gear 30 has a centrally positioned axially extending passageway62 formed therein which is adapted to receive for reciprocationtherethrough an elongated length of flexible wire 64 of which thatportion 66 thereof which projects beyond the rack gear 30 adjacent thejam tooth 36 will be hereinafter referred to as the beam. As will becomemore apparent as this specification progresses, a substantially rigidsolid rod (not shown) may be substituted for the wire 64. A set screw 68is threaded through the rack gear 30 to engage the wire 64 in order tofixedly hold the beam portion 66 in its adjusted position.

In FIGURES 1, 2 and 5, it is seen that the outer end of the beam 66 hasan enlarged cylindrical head 7 0 which is releasably secured within thehollow boss 72 by means of a set screw 74. The boss 72 is integral withand projects laterally from the upper end of an inverted substantiallyhollow frusto-conical housing '76 having opposed open ends. From thedrawings it is also seen that a plurality of radially spaced stabilizingstandards 78 project laterally from the housing 76, the lower ends ofthe standards engaging the support surface 24 to maintain the housing ina substantially upright position.

An inverted open ended substantially hollow frusto conical member 80 isinserted in and nests against the inner side of the housing 76. The baseof the member 80 is formed with a radial flange 82 that abuts againstthe base end of the housing 76 and the other end of the flange 84. As isseen in FIGURE 2, the liner 80 is formed with a plurality oflongitudinally extending, spaced and inwardly projecting ribs 88'. v Theliner 80 is adapted to receive a conventional lead pencil '90 with thepointed end 92 thereof adapted for engagement with the support surface214, the lead pencil'90 being indicated by phantom 1 To utilize the beamtype compass described above,

the draftsman places the pen point 58 over the center point of thecircle or are 94- (see FIGURE 1) to be drawn. The operator holds the cap54 with one hand and with the other hand moves the housing 76 away fromthe rack gear 30 thereby extending the beam 66. This movement iscontinued until the distance between the point 58 and the pencil point921 is slightly greater than the desired radius of the circle or arc 94to be traced or inscribed. Thereafter, the operator tightens the setscrew 68 against the wire 64 and then rotates the knob 48 in a clockwisedirection to effect movement of the rack gear 30 towards the left(reference now being made to FIGURE 2) to obtain the precise desiredradius. The operator then traces the desired curve, are

or circle. In moving the housing 76 and pencil 94- arcuately it will beunderstood thatthe cap 5'4, flange 20 and stabilizing standards 22remain stationary while the main body 12 and rack gear 30are free torotate.

If desired, amechanical pencil could be incorporated withv the housing76.

Having described and. illustrated one embodiment of this invention indetail, it will be understood that the same has been offered merely byway of example, and that the instant invention is to be limited only bythe scope of the appended claims.

What is claimed is:

1. A beam compass comprising a relatively stationary base, a pedestalmounted for rotation on the axis of and upstanding from said base, saidbase having a centering pin for engaging a drawing surface, saidpedestal having a radial bore extending therethrough, a rack barslidably supported through said bore, said rack bar havinglongitudinally spaced teeth on a side thereof, said pedestal having aninternal recess opening to said radial bore, a worm located in saidrecess and meshed with the rack bar teeth, said worm having a shaftjournaled through the pedestal and having thereon a pinion outside ofthe pedestal, a gear wheel journaled on the pedestal parallel to theworm shaft and meshed with said pinion, a rotating knob secured to saidgear wheel, a hand grip cap rotatably mounted on the upper end of thepedestal, said rack bar having an outer end and a longitudinal boreextending to said outer end, a beam having an inner end portion slidablyengaged in said longitudinal bore and an outer end portion extendingbeyond the outer end of the rack bar, means for locking the beam inlongitudinally adjusted positions in the rack bar, and drawing surfaceengaging scriber housing means connected to and depending from the outerend portion of the beam.

2. A beam compass comprising a relatively stationary base, a pedestalmounted for rotation on the axis of and upstanding from said base, saidbase having a centering pin for engaging a drawing surface, saidpedestal having a radial bore extending therethrough, a rack barslidably supported through said bore, said rack bar havinglongitudinally spaced teeth on a side thereof, said pedestal having aninternal recess opening to said radial bore, a worm located in saidrecess and meshed with the rack bar teeth, said worm having a shaftjournaled through the pedestal and having thereon a pinion outside ofthe pedestal, a gear wheel journaled on the pedestal parallel to theworm shaft and meshed with said pinion, a rotating knob secured to saidgear wheel, a hand grip cap rotatably mounted on the upper end of thepedestal, said rack bar having an outer end and a longitudinal boreextending to said outer end, a beam having an inner end portion slidablyengaged in said longitudinal bore and an outer end portion extendingbeyond the outer end of the rack bar, means for locking the beam inlongitudinally adjusted positions in the rack bar, and drawing surfaceengaging scriber housing means connected to and depending from the outerend portion of the beam, said housing means comprising a verticaltubular housing having open upper and lower ends, lateral feet on saidhousing and extending below said lower end to engage a drawing surface,a scriber receiving liner secured in the housing.

3. A beam compass comprising a relatively stationary base, a pedestalmounted for rotation on the axis of and upstanding from said base, saidbase having a centering pin for engaging a drawing surface, saidpedestal having a radial bore extending therethrough, a rack barslidably supported through said bore, said rack bar havinglongitudinally spaced teeth on a side thereof, said pedestal having aninternal recess opening to said radial bore, a worm located in saidrecess and meshed with the rack bar teeth, said worm having a shaftjournaled through the pedestal and having thereon a outside of thepedestal, a gear Wheel journaled on the pedestal parallel parallel tothe worm shaft and meshed with said pinion, a rotating knob secured tosaid gear wheel, a hand grip cap rotatably mounted on the upper end ofthe pedestal, said rack bar having an outer end and a longitudinal boreextending to said outer end, a beam having an inner end portion slidablyengaged in said longitudinal bore and an outer end portion extendingbeyond the outer end of the rack bar, means for locking the beam inlongitudinally adjusted positions in the rack bar, and drawing surfaceengaging scriber housing means connected to and depending from the outerend portion of the beam, said housing means comprising a verticaltubular housing having open upper and lower ends, lateral feet on saidhousing and extending below said lower end to engage a drawing surface,a scriber receiving liner secured in the housing, said housing having alateral boss thereon having a fluid bore in which the outer end of thebeam is removably engaged, and means securing the beam in place in saidfluid bore.

References Cited in the file of this patent UNITED STATES PATENTS336,868 Pratt Feb. 23, 1886 601,455 Wildman et a1 Mar. 29, 1898 811,237Merritt Jan. 30, 1906 992,819 Springer May 23, 1911 1,005,827 GombartsOct. 17, 1911 1,304,501 Menin et a1. May 20, 1919 1,948,952. WalleriusFeb. 27, 1934 2,296,279 Hamilton Sept. 22, 1942 2,324,041 Suverkop July13, 1943 2,523,237 Richardson Sept. 19, 1950 2,556,240 Valentine et alJune 12, 1951 2,607,990 Payamps ...1 Aug. 26, 1952 FOREIGN PATENTS 5,809Great Britain 1898 6,306 Great Britain 1899 116,118 Germany Dec. 28,1900 589,174 Great Britain June 12, 1947 OTHER REFERENCES PopularMechanics magazine, July 1945, page 139. (Copy in 33-270.)

